[Effects of overexpression of atpA, purHD and ndh on the growth of Escherichia coli DH5alpha].
OBJECTIVE
To study the mechanism of the differences in cell growth and acetate production between Escherichia coli DH5alpha and its acetate-tolerant mutant DA19.


METHODS
Based on our previous analysis of the proteome and mass and energy balances for both strains, we first amplified the genes of atpIBEFHAGDC, purHD, and ndh, their regulation regions, as well as the regulation region of nuoA-N in both strains by PCR, and compared the sequences. Then, we constructed the recombinant strains DH5alpha (pTrc99a-atpA), DH5alpha (pTrc99a-purHD) and DH5alpha (pTrc99a-ndh) to study the effect of overexpression of atpA, purHD and ndh in DH5alpha on growth.


RESULTS
The sequences of the structural genes and the regulation regions in the two strains were completely identical with those of E. coli K-12. Overexpression of atpA, purHD and ndh separately in DH5alpha improved cell growth to some extent.


CONCLUSIONS
Overexpression of ndh, purHD and atpA resulted in improved growth of DH5alpha, but the growth of these recombinant strains was still lower than that of DA19, indicating the importance of global regulation to the cellular metabolism.
Zhang
Yanjun
Y
State Key Laboratory of Bioreactor Engineering, East China University of Science & Technology, Shanghai 200237, China. iknow@126.com
Zhang
Xiaoyun
X
Li
Zhimin
Z
Ye
Qin
Q
D000085:Acetates / Q000378:metabolism; D002457:Cell Extracts / Q000032:analysis; D049109:Cell Proliferation; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000235:genetics* / Q000254:growth & development* / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D036781:Fimbriae Proteins / Q000235:genetics / Q000378:metabolism*; D015870:Gene Expression; D009154:Mutation; D009245:NADH Dehydrogenase / Q000235:genetics / Q000378:metabolism*; D010957:Plasmids / Q000235:genetics; D016133:Polymerase Chain Reaction; D017422:Sequence Analysis, DNA
D000085:Acetates; C078802:AtpA protein, E coli; D002457:Cell Extracts; D029968:Escherichia coli Proteins; D036781:Fimbriae Proteins; C088908:NADH dehydrogenase II; D009245:NADH Dehydrogenase